A conventional Ethernet packet is formed by 8 bytes of preamble then followed by at least 64 bytes of payload and then separated by an interpacket gap (IPG). It is advantageous to add additional tag bytes to each packet to help with internal switch and switch fabric operations. A packet to which tag bytes are added will be referred to herein as a tagged packet.
Since a tagged packet requires more bandwidth than a conventional packet, the ports in the switch fabric are generally overclocked so that the ports can keep up with the traffic rates seen on the network. However overclocking requires more power consumption. Hence it is advantageous to minimize the overclocking required.
One technique that may be used to reduce the amount of overclocking required is to “steal bandwidth” from the preamble by substituting some of the preamble bytes with the tag bytes. Another technique is to “steal bandwidth” by reducing the IPG between packets. In 10GBASE-R, 100GBASE-R, and 100GBASE-P Ethernet networks, for example, a physical coding sublayer (PCS) in a physical layer (PHY) poses some challenges in restricting how the IPG can be reduced.